A semiconductor structure and a method for forming the same are provided. The method includes forming a source/drain structure in a substrate and forming a metal layer over the source/drain structure. The method for manufacturing a semiconductor structure further includes performing an annealing process such that a portion of the metal layer reacts with the source/drain structure to form a metallic layer on the source/drain structure. The method for manufacturing a semiconductor structure further includes performing an etching process to remove an unreacted portion of the metal layer on the metallic layer and forming a contact over the metallic layer. In addition, the etching process includes using an etching solvent, and the etching solvent includes (a) a first component, including H2SO4, HCl, HF, H3PO4, or NH4OH and (b) a second component, including propylene carbonate, ethylene carbonate, diethyl carbonate, acetonitrile, or a combination thereof.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method for manufacturing a semiconductor structure, comprising: forming a source/drain structure in a substrate; forming a metal layer over the source/drain structure; performing an annealing process such that a portion of the metal layer reacts with the source/drain structure to form a metallic layer on the source/drain structure; performing an etching process to remove an unreacted portion of the metal layer on the metallic layer; and forming a contact over the metallic layer, wherein the etching process comprises using an etching solvent, and the etching solvent comprises (a) a first component, comprising H2 s O 4 , HCl, HF, H 3 PO 4 , or NH 4 OH; and (b) a second component, comprising propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), acetonitrile, or a combination thereof.
2. The method for manufacturing a semiconductor structure as claimed in claim 1 , wherein a volume ratio of the first component to the second component in the etching solvent is in a range from about 0.05:100 to about 1:10.
3. The method for manufacturing a semiconductor structure as claimed in claim 1 , wherein the etching solvent further comprises (c) a third component, comprising H2O2 or ozone.
4. The method for manufacturing a semiconductor structure as claimed in claim 3 , wherein a volume ratio of the first component to the third component in the etching solvent is in a range from about 0.05:0.0001 to about 1:0.1.
5. The method for manufacturing a semiconductor structure as claimed in claim 3 , wherein a volume ratio of the first component to the second component to the third component in the etching solvent is in a range from about 0.05:10:0.0001 to about 1:10:0.1.
6. The method for manufacturing a semiconductor structure as claimed in claim 3 , wherein an oxide film is formed on sidewalls of the source/drain structure after the etching process.
7. The method for manufacturing a semiconductor structure as claimed in claim 1 , wherein the source/drain structure is a raised source/drain structure formed in a fin structure over the substrate.
8. The method for manufacturing a semiconductor structure as claimed in claim 1 , wherein the source/drain structure is a raised source/drain structure formed in a nanowire structure over the substrate.
9. The method for manufacturing a semiconductor structure as claimed in claim 1 , wherein the etching process is performed at a temperature in a range from about 20° C. to about 150° C.
10. A method for manufacturing a semiconductor structure, comprising: forming a raised source/drain structure having a top portion and a bottom portion over a substrate; forming a metal layer over the top portion of the raised source/drain structure; performing an annealing process such that a portion of the metal layer reacts with the top portion of the raised source/drain structure to form a metallic layer; performing an etching process to remove an unreacted portion of the metal layer on the metallic layer; and forming a contact over the metallic layer, wherein the etching process comprises using an etching solvent, and the etching solvent comprises (a) a first component, comprising H 2 SO 4 , HCl, HF, H 3 PO 4 , or NH 4 OH; and (b) a second component, comprising propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), acetonitrile, or a combination thereof.
11. The method for manufacturing a semiconductor structure as claimed in claim 10 , wherein a volume ratio of the first component to the second component in the etching solvent is in a range from about 0.05:100 to about 1:10.
12. The method for manufacturing a semiconductor structure as claimed in claim 10 , wherein the etching solvent further comprises (c) a third component, comprising H 2 O 2 or ozone, wherein a volume ratio of the first component to the third component in the etching solvent is in a range from about 0.05:0.0001 to about 1:0.1.
13. The method for manufacturing a semiconductor structure as claimed in claim 12 , wherein an oxide film is formed on sidewalls of the bottom portion of the raised source/drain structure.
14. The method for manufacturing a semiconductor structure as claimed in claim 12 , wherein the etching process is performed at a temperature in a range from about 20° C. to about 150° C.
15. The method for manufacturing a semiconductor structure as claimed in claim 1 , further comprising: forming a fin structure over the substrate; and forming a gate structure across the fin structure, wherein the step of forming the source/drain structure in the substrate includes forming a source/drain structure in the fin structure.
16. The method for manufacturing a semiconductor structure as claimed in claim 15 , wherein a volume ratio of the first component to the second component in the etching solvent is in a range from about 0.05:100 to about 1:10.
17. The method for manufacturing a semiconductor structure as claimed in claim 15 , wherein the etching solvent further comprises (c) a third component, comprising H 2 O 2 or ozone.
18. The method for manufacturing a semiconductor structure as claimed in claim 15 , wherein the source/drained structure has a dent at its bottom portion.
19. The method for manufacturing a semiconductor structure as claimed in claim 17 , wherein an oxide film is formed on sidewalls of the source/drain structure after the etching process.
20. The method for manufacturing a semiconductor structure as claimed in claim 19 , wherein the contact is in direct contact with the oxide film.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
October 28, 2014
July 5, 2016
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